This application relates generally to disc drives and more particularly to a system for filling a disc drive with a gas other than air.
A disc drive typically includes a base to which various components of the disc drive are mounted. A top cover cooperates with the base to form a housing that defines an internal, sealed environment for the disc drive. Filling the sealed environment of disc drives with gases other than air can enhance their performance. For example, low-density inert gases such as helium can reduce the aerodynamic drag between the discs and their associated read/write heads by a factor of approximately five-to-one compared to operating in air. This reduced drag results in reduced power requirements for the spindle motor. A helium filled drive thus uses substantially less power than a comparable disc drive that operates in an air environment. At the same time, the helium gas conducts away heat generated during operation of the disc drive more effectively than air.
Despite the advantages of helium filled drives, such drives have not been commercially successful. This is mainly due to problems associated with the helium leaking from the disc drives over time. As the helium leaks out, air leaks in causing undesirable effects in the operation of the disc drives and possibly causing the disc drives to fail. For example, the increased concentration of air may increase the forces on the read/write head due to turbulent airflow within a drive and it may cause noise and/or the heads to fly at too great a distance above the discs. Thus, helium filled drives must be filled when they are first operated. Additionally, after helium has leaked from such drives they must be either discarded or refilled with helium. Filling disc drives with helium to a desired pressure and concentration can be time-consuming and difficult.
Accordingly there is a need for an improved system that can effectively fill a disc drive with a gas other than air, such as helium, to a desired concentration. The present invention provides a solution to this and other problems, and offers other advantages over the prior art.
Against this backdrop the present invention has been developed. One embodiment of the invention is a system for filling an enclosed environment of a disc drive with a gas other than air. The filling system includes a filling system connection apparatus that can be connected to a corresponding disc drive connection apparatus that is in turn connected to the enclosed environment of the disc drive. By way of example, the connection apparatus could be a Schrader-type valve. A vacuum source, such as a vacuum pump, and a source of gas other than air, such as a pressurized gas tank, can be connected to the filling system connection apparatus. The filling system also includes a pressure sensor that can produce a pressure signal representative of the pressure within the enclosed environment of the disc drive. A control module receives the pressure signal and directs one of the vacuum source and the source of gas other than air through the filling system connection apparatus to the enclosed environment of the disc drive.
Another embodiment of the present invention is a method of filling an enclosed environment of a disc drive with a gas other than air. The enclosed environment is connected to a vacuum source. After the enclosed environment has reached a predetermined low pressure range of from about 5 torr to about 100 torr, it is disconnected from the vacuum source, such as by closing a valve. The enclosed environment is then connected to a source of gas other than air, such as by opening a valve. After the enclosed environment has reached a predetermined high pressure, the vacuum source is disconnected from the enclosed environment, such as by closing the valve.
These and various other features as well as advantages which characterize the present invention will be apparent from a reading of the following detailed description and a review of the associated drawings.